Technical Innovations
Loctite's cured-in-place gasketing technology
 Loctite cured-in-place gasketing material can be quickly applied using an automated process. |
OEMs and suppliers have come to rely on cured-in-place gasketing (CIPG) materials for a range of vehicle applications, according to Loctite. In keeping with that trend, the company has commercialized a cured-in-place, polyether foam material to prevent BSR (buzz, squeak, and rattle), vibration, and wind noise in exterior applications.
The material can also be used in myriad interior applications where pressure-sensitive adhesive-backed foam tapes and some mechanical fastening methods have traditionally been used. Use of these methods can entail high labor and material costs. The gasketing material, on the other hand, is economical, easy to apply and cure, and can help to reduce overall vehicle weight, according to the company.
"In the (automotive) B-pillar applications, where our new polyether foam gasketing material is currently in use, OEMs benefit from the material's ability to adhere to a wide variety of substrates and its lubricious post-cure surface that allows mating parts to be slid into place with minimum adjustment force," said Mark Neuenschwander, Loctite CIPG Program Manager. The polyether foam is very versatile, he added, curing at room temperature or in just 10 min. at 100°C (212°F) and offering improved adhesion to hard-coated acrylic polycarbonate, and is heat-resistant to 120°C (248°F).
In addition to the new polyether foam material, liquid CIPG materials are available as silicone and ethylene acrylic rubber formulations that solidify via heat- or light-cure methods, according to Loctite. Heat cures appropriate gasketing materials completely after a few minutes of exposure to 150°C (302°F). Light cures photo-initiated gasketing materials in seconds upon exposure to the right wavelength of UV or visible light. For high-speed production, light- and heat-curing silicones are the most popular formulations available. Heat-cure chemistries deliver tough, strong compression gaskets and resist degradation in hot lubricating fluids, coolants, and fuels. Light-curing materials offer extremely rapid cure to depths of about 6 mm (0.2 in). Both types of gaskets are commonly used in conveyor-driven continuous cure systems.
Rubber CIPG pastes are available in durometer OO through Shore A range. If standard dense rubber gaskets are too hard, foam silicone gasketing materials with air incorporated into the formulation can deliver sound attenuation, vibration reduction, and high compressibility.
Silicone foam compression gaskets are suitable for such applications as electronic module covers, air cleaner housings, door panels, door handles, wiper motors, connector seals, fuse box covers, lens covers, and timing belt covers. When coolants, motor oils, and fuels must be contained and isolated—for example, in water pump housings, oil pans, rocker-arm covers, and intake manifolds—standard silicone rubber gasketing materials are a viable option. Standard silicone rubbers are also used in less hostile environments such as lamp housings, electrical boxes, and air filter housings to prevent environmental intrusion of water and solid particles.
Because they can be quickly and inexpensively applied using an automated process, gaskets made via CIPG allow OEMs to replace the costly and time-consuming hand assembly of cut or molded rubber gaskets, according to Loctite. "Unlike conventional gasketing, CIPG can be outsourced to lower-tier suppliers, simplifying the OEM's production line and adding value at the most economical point in the manufacturing process," said Neuenschwander.
With CIPG, gaskets also form and mold precisely to the part, eliminating the need to inventory specific gasket sizes and shapes. In addition, the company said, they strongly adhere to a variety of substrates including metals and many engineered plastics. These materials can be designed with relatively low adhesion, making them suitable for use on parts that will require service and gasket replacement. Service conditions determine what materials are best for an automotive application. Silicones and ethylene acrylics are resistant to a wide range of underhood fluids, including crankcase and gear oils, automatic transmission fluid, and coolants.
- Patrick Ponticel
Wire and cable sleeving from Federal-Mogul
An improved wire and cable sleeving product, called FlexWrap 2310, delivers improved abrasion resistance while maintaining its thermal rating, flexibility at low temperature, and resistance to fluids. The product from Federal-Mogul Systems Protection Group also features a new self-closing system in which the hook is integrally woven into the material, providing for easy installation and removal (no tools required), inspection, rework, and component replacement.
The body of the loop portion of FlexWrap is composed entirely of polyester materials, whereas the hook is composed of nylon mono-filaments, creating a low-bulk, lightweight product, according to the company. The hook is not subject to sew-line failure because it is integrally woven.
Testing to SAE ARP 1536A shows the product to be three times more abrasion-resistant than FlexWrap 2300. The improved product, Federal-Mogul said, easily accommodates breakouts, requires no open end for applications, and does not trap heat or moisture. The space-saving closure maintains low profile for flat cables and harnesses.
- Patrick Ponticel
